Parkinson's disease (PD) is a degenerative neurological condition that affects the motor system and is often accompanied by depression and cognitive impairment. Although symptoms can be somewhat controlled by medications, drug therapy for advanced Parkinson's disease is unsatisfactory. Stereotactic implantation of human embryonic dopamine cells into the putamen of patients with advanced Parkinson's disease is a new experimental procedure that has been shown to ameliorate some of the symptoms of the disease. However, because these positive results have been observed in open clinical trials, it is important to establish the effectiveness of this procedure through a controlled placebo, double-blind study. Such a study has recently been approved by the National Institutes of Health. The development of the present proposal has been encouraged by the principal investigator of that grant, Dr. Curt Freed. The objective of this proposed longitudinal outcome study is to investigate the influence of two experimental treatments on the quality of life of persons with idiopathic Parkinson's disease. Treatments include: 1) embryonic tissue implant and 2) sham surgery consisting of craniotomy alone. In the double-blind study, quality of life is assessed by a single global rating item. In significant contrast, this application proposes to measure psychosocial and quality of life outcomes across a number of dimensions. Forty patients will be recruited for the study. Patients receiving the sham surgery will be offered the neural transplant one year after the initial procedure. Outcome assessment will focus on perceived quality of life. In addition to specific measures of emotional and psychological functioning obtained from the patient, information will be solicited from the patient's significant other and from medical personnel in New York working with patients in the study. Measures will be obtained at baseline, 3, 6, 9, 12, and 24 months after surgery. The treatment group assignment will be revealed for each patient at the 12 month assessment. For patients receiving the sham surgery who elect to receive the neural implant, additional measures will be obtained 3, 6, 9, 12, and 24 months after the second surgery. The study has one primary aim and one secondary aim. First, the study will determine if neural implant surgery improves the quality of life for Parkinson patients more than placebo surgery. Second, the study will determine the extent to which perception of the type of treatment received is linked to quality of life.